The present invention relates to a microwave module in which a transmitting portion circuit and a receiving portion circuit are integrated.
In order to suppress mutual interference between a transmitting portion circuit and a receiving portion circuit included in a microwave module, there has been adopted such means that the respective circuits are constructed with different substrates and a shielding member made of a metal plate or electric wave absorber is provided between both, or the distance between the substrates is made large.
FIG. 4 is a structural view of a microwave module disclosed in Japanese Patent Unexamined Publication No. Sho. 64-25500. 
In FIG. 4, reference numeral 50 designates an FET (field-effect transistor); reference numerals 51 and 52, circuits made of microstrip lines; reference numeral 53, a shielding member such as an electric wave absorber; and reference numeral 54, a cut into which the shielding member 53 is fitted.
In the microwave module having the structure shown in FIG. 4, in order to prevent mutual interference by an electromagnetic field between the circuits 51 and 52 provided in a housing of the microwave module, the shielding member 53 is provided along the cut 54, so that isolation between the circuits is raised.
As described above, in the conventional microwave module, in order to suppress the mutual interference by the electromagnetic field between the transmitting and receiving circuits in the microwave transmitting and receiving module, the respective circuits are constructed on different substrates, and further, the shielding member made of the metal or electric wave absorber is provided between both. However, in that case, the size and weight of the module is large.
The present invention has been made to solve the foregoing problem, and has an object to provide a microwave module in which mutual interference by an electromagnetic field between element circuits in the module can be suppressed, and the circuits can be arranged close to each other without requiring a shielding member, so that miniaturization of the module can be realized.
A microwave module of the present invention comprises a transmitting portion circuit and a receiving portion circuit, wherein the transmitting portion circuit and the receiving portion circuit are respectively constructed by transmission lines of different kinds in which polarization planes are orthogonal to each other, and are constructed on the same surface of the same substrate.
Further, one of the transmitting portion circuit and the receiving portion circuit is constructed by a microstrip line, and the other is constructed by a coplanar line.
Furthermore, one of the transmitting portion circuit and the receiving portion circuit is constructed by a microstrip line, and the other is constructed by a slot line.